Detuning a MRT receive antenna

Patent metadata

Field	Value
Publication number	US-10145912-B2
Application number	US-201615131201-A
Country	US
Kind code	B2
Filing date	Apr 18, 2016
Priority date	Apr 30, 2015
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

An arrangement for detuning a receive antenna, a detunable magnetic resonance coil, and a magnetic resonance device having a detunable magnetic resonance coil are provided. The arrangement includes a receive antenna having at least one first capacitance, wherein radiofrequency signals from a magnetic resonance examination may be received by way of the receive antenna. The arrangement furthermore includes a switchable detuning circuit containing the first capacitance switched to form an oscillating circuit and a first inductance, and a switching device having a first and a second connection point to deliver a voltage between the first and a second connection point, and one or more transistors. The switching device switches the oscillating circuit to a high impedance level with aid of the one or more transistors on delivery of a positive voltage to the first connection point, preventing a radiofrequency signal from being received by way of the receive antenna.

First claim

The invention claimed is:

1. An arrangement for detuning a receive antenna, the arrangement comprising:
a receive antenna having at least one first capacitance, wherein radiofrequency signals from a magnetic resonance examination are receivable by way of the receive antenna;
a switchable detuning circuit that contains the at least one first capacitance switched to form an oscillating circuit and a first inductance; and
a switching device comprising one or more transistors, a first connection point, and a second connection point configured to deliver a voltage between the first connection point and the second connection point, wherein at least one transistor of the one or more transistors is a field-effect transistor having a gate terminal, a source terminal, and a drain terminal, and wherein the gate terminal is connected to the first connection point,
wherein the switching device is configured to switch the oscillating circuit to a high impedance level with aid of the one or more transistors on delivery of a positive voltage to the first connection point so as to prevent a radiofrequency signal from being received by way of the receive antenna.

2. The arrangement of claim 1 , wherein the switching device further comprises at least one diode.

3. The arrangement of claim 1 , wherein the field-effect transistor is a metal-oxide-semiconductor field-effect transistor.

4. The arrangement of claim 1 , wherein the field-effect transistor is a field-effect transistor based on III-V semiconductors.

5. The arrangement of claim 1 , wherein the field-effect transistor is a field-effect transistor based on gallium nitride.

6. The arrangement of claim 1 , wherein the switching device has a diode connected to the gate terminal and the first connection point in a forward direction, and connected to the source terminal in a reverse direction.

7. The arrangement of claim 1 , wherein the switching device has a connection between the second connection point and the drain terminal.

8. The arrangement of claim 1 , wherein the field-effect transistor exhibits a behavior analogous to an inverse diode.

9. The arrangement of claim 1 , wherein at least one transistor of the one or more transistors is a bipolar transistor.

10. The arrangement of claim 9 , wherein the bipolar transistor comprises an insulated gate electrode.

11. The arrangement of claim 1 , wherein the switching device comprises at least two transistors connected in series.

12. The arrangement of claim 1 , wherein the switching device comprises at least one resistance for current limiting.

13. The arrangement of claim 1 , wherein the switching device comprises at least one inductance for current limiting and/or for filtering.

14. The arrangement of claim 1 , wherein the receive antenna is a loop antenna and/or dipole antenna.

15. A magnetic resonance coil comprising:
an arrangement for detuning a receive antenna, the arrangement comprising:
a receive antenna having at least one first capacitance, wherein radiofrequency signals from a magnetic resonance examination are receivable by way of the receive antenna;
a switchable detuning circuit that contains the at least one first capacitance switched to form an oscillating circuit and a first inductance; and
a switching device comprising one or more transistors, a first connection point, and a second connection point configured to deliver a voltage between the first connection point and the second connection point, wherein at least one transistor of the one or more transistors is a field-effect transistor having a gate terminal, a source terminal, and a drain terminal, and wherein the gate terminal is connected to the first connection point,
wherein the switching device is configured to switch the oscillating circuit to a high impedance level with aid of the one or more transistors on delivery of a positive voltage to the first connection point so as to prevent a radiofrequency signal from being received by way of the receive antenna.

16. The magnetic resonance coil of claim 15 , wherein the magnetic resonance coil is a local coil.

17. A magnetic resonance device comprising:
at least one magnetic resonance coil, the magnetic resonance coil comprising:
an arrangement for detuning a receive antenna, the arrangement comprising:
a receive antenna having at least one first capacitance, wherein radiofrequency signals from a magnetic resonance examination are receivable by way of the receive antenna;
a switchable detuning circuit that contains the at least one first capacitance switched to form an oscillating circuit and a first inductance; and
a switching device comprising one or more transistors, a first connection point, and a second connection point configured to deliver a voltage between the first connection point and the second connection point, wherein at least one transistor of the one or more transistors is a field-effect transistor having a gate terminal, a source terminal, and a drain terminal, and wherein the gate terminal is connected to the first connection point,
wherein the switching device is configured to switch the oscillating circuit to a high impedance level with aid of the one or more transistors on delivery of a positive voltage to the first connection point so as to prevent a radiofrequency signal from being received by way of the receive antenna.

18. The magnetic resonance device of claim 17 , wherein the at least one magnetic resonance coil is a local coil.

Assignees

• Huber Klaus
• Rehner Robert
• Vester Markus
• Siemens Ag

Inventors

• Huber Klaus
• Rehner Robert
• Vester Markus

Classifications

• G01R33/341

  comprising surface coils · CPC title

• G01R33/3657 Primary

  Decoupling of multiple RF coils wherein the multiple RF coils do not have the same function in MR, e.g. decoupling of a transmission coil from a receive coil · CPC title